1. Field of the Invention
The present invention relates to an apparatus for externally draining fluid from a body, in particular cerebral spinal fluid from a brain, which includes an antisiphon device that is capable of preventing reflux of fluid while allowing fluid to flow out of the brain and that is capable of preventing excessive fluid flow during mishandling.
2. Description of the Prior Art
Heretofore, various external ventricular draining apparatus and external ventricular monitoring and draining apparatus have been proposed. Such apparatus includes a ventricular catheter whose distal end is placed in the ventricle of the brain of a patient. This apparatus relies on a siphon created by gravity to drain excess fluid from the ventricle.
The ventricular catheter described above has a proximal end which has a luer connector attached to it. The luer connector is in turn connected to a connector on one end of a piece of tubing. The tubing is normal surgical fluid tubing and extends a short distance into the top of a drip chamber. The drip chamber is normally positioned in a vertical plane and is a device commonly used in fluid drainage by doctors and nurses. The bottom end of the drip chamber has a connector which accommodates surgical tubing.
Frequently, tubing is connected to the bottom of the drip chamber and travels a short distance downward with respect to gravity and is sometimes connected to a stopcock for sampling of the cerebral fluid. This stopcock has connectors means at both ends to accommodate surgical tubing which runs a the valve from the drip chamber and then out of the valve and downward a short distance to a drainage bag. This bag is normally a common plastic bag used to accumulate cerebral fluid. The bag readily connects to the surgical tubing to allow replacement when full.
In operation, the apparatus is clamped to a pole such as an I.V. pole and placed at a height relative to the height of the brain of a patient which will allow gravity to remove any excess cerebral fluid. Drainage occurs when the pressure of the body fluid exceeds the pressure determined by the height of the drainage apparatus relative to the height of the patient's brain. This height is critical since it must be positioned to only allow drainage of excess cerebral fluid. If the height of the system is too high, the pressure of the system is greater than that of the fluid pressure in the patient's body and reverse flow will occur. If the height of the system is too low, the system acts as a siphon and too much fluid is drained from the patient which can cause severe injury to a patient.
It is possible through accident, mishandling of the system or other uncontrolled events that the height of the system does fall drastically below the height of the patient's brain. Therefore, it is desirable to provide such a system with a device which will prevent any mishandling or error in the set-up and use of the external drainage system to prevent injury to a patient.
As will be described in greater detail hereinafter, the apparatus of the present invention differs from the apparatus previously proposed by providing an antisiphon device contained within an external drainage system as described above and positioned between a ventricular catheter and a drip chamber in a vertical plane.
As described in greater detail hereinafter, the antisiphon device is elongated and has openings at each end with a connector and being sized to accommodate surgical tubing from the ventricular catheter with a connector at the top end having an outflow tract therein and being capable of connecting to the drip chamber.
This antisiphon device is constructed in such a way so that in cases of no flow from the brain of a patient, the inflow tract is closed preventing reflux of fluid. Additionally, the device is constructed in such a way so that in cases of normal fluid flow from the brain, the inflow tract is open and fluid is allowed to pass freely into and through the antisiphon device and out the outflow tract, into the drip chamber.
Finally, the device is constructed in such a way so that in the event the height of the system drastically falls below the height of the brain of the patient, which will cause excessive flow, the outflow tract of the device is blocked which prevents fluid flow as well as excess drainage and damage to the patient.